How to grow macadamia nuts

What you need to know about a macadamia tree

Name: macadamia, Macadamia integrifolia, Macadamia tetraphylla.

Height: up to 20m, although most home varieties reach only 2–4m, with dwarf varieties available that grow only 1–2m, which are perfect for pots.

Foliage: evergreen glossy foliage.

Climate: a tropical tree that grows well in all frost -free climates, although extra protection is required in cold climates during establishment.

Soil: prefers a well-drained soil enriched with compost and manure. Avoid artificial fertilisers unless they are designed for Australian natives.

Position: full sun, protected from strong winds.

Flowering and fruiting: strings (also known as panicles) of white or pink fluffy flowers are produced in spring, followed by the nuts, which develop over several months. Nuts are ready to harvest when the shells begin to crack.

Feeding: apply a fertiliser specifically developed for Australian natives, in early spring.

Watering: shallow-rooted tree, so water regularly, especially during dry hot weather, and mulch to conserve soil moisture.

Appearance and characteristics of a macadamia tree

A large evergreen tree with glossy leaves, macadamia is a stunning shade tree with striking tassels of flowers in spring. It can be a little fussy to get started, but once established will be a valuable ornamental and edible tree. Macadamia is not a fast cropping plant, but it will be worth the wait, producing nuts in 5–10 years, with full production expected in 15–20 years.

Uses for a macadamia tree

While there is no doubt that macadamias are delicious nuts, the tree itself is also suitable for home gardens as a lush shade tree or hedge, creating a verdant evergreen screen with stunning strings (panicles) of flowers in spring, followed by up to 10kg of nuts per tree from autumn to late spring.

How to plant and grow a macadamia

1. Prepare the soil prior to planting with compost and decomposed manure.
2. Plant at the same height as it was in the pot, and backfill, pressing the soil down firmly.
3. Water to remove any air pockets.
4. Apply a layer of mulch around the tree to a diameter of around 1m.
5. In cold climates, place 3–4 stakes around the tree and wrap in hessian during periods of frost for the first few years to help the tree establish. This also helps protect young trees from wind.

Caring for a macadamia tree

The macadamia is a shallow-rooted tree, so regular watering is required, especially during the first few years and in dry hot weather. Once established, water weekly from spring to autumn. Mulch to conserve soil moisture.

An Australian native related to banksia and grevillea, the macadamia is sensitive to some fertilisers. Always use a fertiliser designed specifically for native plants. Improve soil at planting time with compost and decomposed manure. Apply a slow-release native fertiliser in early spring, followed by liquid applications of fish and seaweed solutions periodically during summer to ensure the tree has ample nutrients while setting its crop.

How and when to prune a macadamia tree

Regular pruning is not required. Instead, prune only when required to control shape or height.

Diseases and pests

Depending on your climate, macadamia can be relatively pest-free. To protect it, encourage beneficial insects to the garden, such as parasitic wasps to prevent nut borers and weevils becoming a problem in tropical and sub-tropical areas. If you do get an infestation of pests, try Yates Success or Eco Neem.

How to propagate a macadamia

Macadamia can be propagated by grafting or seed.

Growing macadamia from seed

1. Seed should be planted as soon as possible once it has fallen from the tree.
2. Grow in pots until it reaches at least 30cm high.
3. Transplant out into the garden in a protected position in early spring.

Grafting and budding

Grafting and budding is an advanced technique of propagation which is usually done onto the rootstock of Macadamia tetraphylla, the most climate-tolerant species of macadamia, and the least fussy. Once the graft or bud has taken on the rootstock, remove all shoots that grow beneath the graft to encourage the top growth to flourish.

Safety tip

If using products to deal with pests, diseases or weeds, always read the label, follow the instructions carefully and wear suitable protective equipment. Store all garden chemicals out of the reach of children and pets.

If you like this then try

Almond: a popular backyard nut tree related to peaches.

Dwarf fruit tree: perfect for pots and small gardens. 

Banana: an excellent fruiting plant for the home garden.

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